An Ex Vivo Model of Left Ventricular Dilation and Functional Mitral Regurgitation to Facilitate the Development of Surgical Techniques

2013 ◽  
Vol 16 (6) ◽  
pp. 329
Author(s):  
Eric Monnet ◽  
Kristal Pouching
Keyword(s):  
Mitral Regurgitation ◽  
Papillary Muscle ◽  
Ex Vivo ◽  
Surgical Techniques ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Ex Vivo Model ◽  
Ischemic Disease ◽  
Posterior Papillary Muscle ◽  
Annular Dilation

<p><b>Objective:</b> Functional mitral regurgitation (FMR) is a common sequelae of myocardial ischemic disease. It results from annular dilation and outward rotation of the posterior papillary muscle. Different surgical techniques are under investigation for the treatment of FMR. However, an ex vivo model of FMR would be valuable to develop and compare the effect of techniques on the geometry of the left ventricle and the correction of FMR.</p><p><b>Methods:</b> FMR was induced in explanted ovine hearts (n = 12) by manual dilation of the mitral annulus or by posterior papillary muscle repositioning with a patch. Left ventricular dimensions were measured. Mitral regurgitant volume (MRV) was measured in a continuous flow system.</p><p><b>Results:</b> Annular dilation significantly increased MRV from 93.0 � 110.4 to 472.2 � 211.8 mL/min (<i>P</i> = 0.031), and the patch increased it from 37.8 � 55.2 to 365 � 189.6 mL/min (<i>P</i> = 0.031), with no significant differences between the 2 groups. When both techniques were applied, MRV significantly increased to 1383.5 � 567.0 mL/min (<i>P</i> = 0.0005). The left ventricular sphericity index decreased from 3.25 � 0.7 to 2.34 � 0.6 (<i>P</i> = 0.0025) after application of the patch. The posterior papillary muscle was displaced after patch placement, following an outward rotation.</p><p><b>Conclusion:</b> This ex vivo model reproduces annular dilation and outward rotation of the posterior papillary muscle, which are both present during FMR after ischemic myocardial disease. This model could be used to evaluate and compare interventions to treat FMR.</p>

scholarly journals Ex Vivo Model of Functional Mitral Regurgitation Using Deer Hearts

2020 ◽  
Author(s):  
Michal Jaworek ◽  
Andrea Mangini ◽  
Edoardo Maroncelli ◽  
Federico Lucherini ◽  
Rubina Rosa ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Ex Vivo ◽  
Mitral Annulus ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Pathological State ◽  
Preclinical Research ◽  
Ex Vivo Model ◽  
Mitral Valves ◽  
Feasibility Assessment

Abstract Transcatheter therapies are emerging for functional mitral regurgitation (FMR) treatment, however there is lack of pathological models for their preclinical assessment. We investigated the applicability of deer hearts for this purpose. 8 whole deer hearts were housed in a pulsatile flow bench. At baseline, all mitral valves featured normal coaptation. The pathological state was induced by 60-minutes intraventricular constant pressurization. It caused mitral annulus dilation (antero-posterior diameter increase from 31.8 ± 5.6 mm to 39.5 ± 4.9 mm, p = 0.001), leaflets tethering (maximal tenting height increase from 7.3 ± 2.5 mm to 12.7 ± 3.4 mm, p < 0.001) and left ventricular diameter increase (from 67.8 ± 7.5 mm to 79.4 ± 6.5 mm, p = 0.004). These geometrical reconfigurations led to restricted mitral valve leaflets motion and leaflet coaptation loss. Preliminary feasibility assessment of two FMR treatments was performed in the developed model. Deer hearts showed ability to dilate under constant pressurization and have potential to be used for realistic preclinical research of novel FMR therapies.

scholarly journals Left Ventricular Thinning and Distension in Pig Hearts as a Reproducible Ex Vivo Model of Functional Mitral Regurgitation

ASAIO Journal ◽  
2020 ◽  
Vol 66 (9) ◽  
pp. 1016-1024 ◽  
Author(s):  
Elorm J. Agra ◽  
Kirthana Sreerangathama Suresh ◽  
Qi He ◽  
Daisuke Onohara ◽  
Robert A. Guyton ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Ex Vivo ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Ex Vivo Model

Abstract 16874: Papillary Muscle Approximation Relieves Tethering Forces and Improves Systolic Mitral Valve Kinematics in an Ex-Vivo Model of Functional Mitral Regurgitation

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Samantha Zhan Moodie ◽  
Kirthana Sreerangathama Suresh ◽  
Dongyang Xu ◽  
Muralidhar Padala
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Papillary Muscle ◽  
Ex Vivo ◽  
Functional Mitral Regurgitation ◽  
Current Standard ◽  
Ex Vivo Model ◽  
Mitral Valves ◽  
Baseline Values ◽  
Mitral Valve Geometry

Introduction: Undersizing annuloplasty (UA), which is the current standard to correct functional mitral regurgitation (FMR) is effective, but the resulting unphysiological systolic geometry causes FMR recurrence. On the other hand, papillary muscle approximation (PMA), a sub-annular technique, reduces inter-papillary separation and tethering forces, mobilizing the leaflets. Objective: To investigate the effect of PMA on mitral valve tethering forces and systolic coaptation geometry, compared to UA. Methods: A left heart model with pig mitral valves was used to create a tethered mitral valve geometry and to perform surgical repairs ( Fig. A ). Mitral valve geometry, and marginal and strut chordal forces acting on both leaflets were measured. Eight individual pig valves (n=8) were studied, with hemodynamic and mechanics data acquired at normal geometry (BASELINE) ( Fig. B) , after tethering (FMR) ( Fig. C) , undersizing annuloplasty (UA) to size 34 (Edwards Lifesciences Physio ring) ( Fig. D) , papillary muscle approximation (PMA), and combination (PMA+UA). Results: Tenting height, which increased after FMR, was least with PMA (0.46 cm± 0.21) and PMA+UA (0.50± 0.16) but remained significantly high with UA (0.73±0.21, p=0.03) ( Fig. E ). Excursion angles of anterior and posterior leaflets were restored close to baseline values after PMA and PMA+UA but remained significantly tethered after UA ( Fig. F & G ). Tethering of the valve increased the strut and marginal chordae forces from 0.47 and 0.14 N to 0.89 and 0.21 N, an increase of 89% and 50% respectively. PMA reduced the forces by 47% and 34%, and PMA+UA reducing it by 43% and 34%to 0.51 while UA only reduced it by 15% and 20% ( Fig. H & I ). Conclusion: PMA significantly reduced the tethering forces on both marginal and strut chordae of both leaflets. Decrease in tethering forces restored the physiologically favorable valve geometry enabling better leaflet mobility and coaptation compared to UA.

A Novel Quantitative Ex Vivo Model of Functional Mitral Regurgitation

2020 ◽  
Vol 15 (4) ◽  
pp. 329-337
Author(s):  
Chetan Pasrija ◽  
Rachael Quinn ◽  
Mehrdad Ghoreishi ◽  
Thomas Eperjesi ◽  
Eric Lai ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Ex Vivo ◽  
3D Structure ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Ex Vivo Model ◽  
3 Dimensional ◽  
Structured Light Scanner ◽  
Repair Techniques

Objective Durability of mitral valve (MV) repair for functional mitral regurgitation (FMR) remains suboptimal. We sought to create a highly reproducible, quantitative ex vivo model of FMR that functions as a platform to test novel repair techniques. Methods Fresh swine hearts ( n = 10) were pressurized with air to a left ventricular pressure of 120 mmHg. The left atrium was excised and the altered geometry of FMR was created by radially dilating the annulus and displacing the papillary muscle tips apically and radially in a calibrated fashion. This was continued in a graduated fashion until coaptation was exhausted. Imaging of the MV was performed with a 3-dimensional (3D) structured-light scanner, which records 3D structure, texture, and color. The model was validated using transesophageal echocardiography in patients with normal MVs and severe FMR. Results Compared to controls, the anteroposterior diameter in the FMR state increased 32% and the annular area increased 35% ( P < 0.001). While the anterior annular circumference remained fixed, the posterior circumference increased by 20% ( P = 0.026). The annulus became more planar and the tenting height increased 56% (9 to 14 mm, P < 0.001). The median coaptation depth significantly decreased (anterior leaflet: 5 vs 2 mm; posterior leaflet: 7 vs 3 mm, P < 0.001). The ex vivo normal and FMR models had similar characteristics as clinical controls and patients with severe FMR. Conclusions This novel quantitative ex vivo model provides a simple, reproducible, and inexpensive benchtop representation of FMR that mimics the systolic valvular changes of patients with FMR.

scholarly journals Left Ventricular Dilatation and Posterior Papillary Muscle Displacement in an Ex Vivo Pulsatile Model of Functional Mitral Regurgitation

2018 ◽  
Vol 21 (4) ◽  
pp. E275-E280
Author(s):  
Krishaporn Kradangnga ◽  
Eric Monnet
Keyword(s):  
Mitral Regurgitation ◽  
Ex Vivo ◽  
Surgical Techniques ◽  
Left Ventricular ◽  
Ventricular Dilatation ◽  
Functional Mitral Regurgitation ◽  
Heart Model ◽  
Large Patch ◽  
Left Ventricular Dilatation ◽  
Patch Placement

Background: Surgical method of choice for functional mitral regurgitation (FMR) is debatable, since recurrence of FMR post-annuloplasty has been reported in a significant number of cases. Developing a pulsatile FMR heart model by left ventricular dilatation can be a favorable option for usage in the primary stages of developing new surgical techniques that adjunctively targets the posterior papillary muscle (PPM) geometry.Methods: PPM of ex vivo ovine hearts (N = 22) was displaced by three different sizes of patches to induce left ventricular dilatation and FMR. Mitral regurgitation (MR) flow, left ventricular and annular geometry were measured from the dynamic pulsatile flow system before and after patch placement.Results: Outward displacement of PPM was significantly increased in all patch sizes compared to baseline (P = .016, P = .031, and P = .008 from small to large patch, respectively). Left ventricular volume (LVV) significantly increased from 18.53 (15.01-26.03) mL at baseline to 27.5 (19.45-42.46) mL after large patch placement (P = .031). However, the small and medium patch groups did not show significant changes in the LVV after patch placement. MR significantly increased 554 (185-1,919.3) mL/min after applying the large patch compared to baseline (P = .016). There were no significant changes from baseline in MR flow after applying the small and medium patch. Application of the large patch produced the highest proportion of FMR heart models (87.5%, P = .031).Conclusion: The large patch ex vivo pulsatile heart model demonstrated outward displacement of the PPM and significantly produced MR flow. This ex vivo pulsatile heart model can be used to facilitate surgical techniques that targets the PPM displacement in FMR patients.

Abstract 17145: Mitral Leaflet Growth and its Relationship with Functional Mitral Regurgitation in Non-ischemic Left Ventricular Systolic Dysfunction

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Yu Kang ◽  
Xiao-Jing Chen ◽  
Qing Zhang ◽  
Xiao-Ling Sun ◽  
Yu-Chen Chen ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Left Ventricular Systolic Dysfunction ◽  
Systolic Dysfunction ◽  
Normal Subjects ◽  
Left Ventricular ◽  
Area Ratio ◽  
Functional Mitral Regurgitation ◽  
Mitral Leaflet ◽  
Significant Difference ◽  
Annular Dilation

Backgrounds: Recent studies evidenced growth of the mitral leaflet (ML) in patients with functional mitral regurgitation (FMR), casting doubt on the traditional understanding of FMR. The aim of this study was to explore whether growth of ML occurs in patients with non-ischemic left ventricular (LV) systolic dysfunction and to examine whether there was any relationship between the growth of ML and the development of FMR. Methods: Echocardiographic examination was performed in 3 groups of patients: patients with non-ischemic LV systolic dysfunction [LV ejection fraction (EF) <50%] and significant FMR (MR jet area ratio≥20%) (group1, n=40), patients with non-ischemic LV systolic dysfunction but no significant FMR (MR jet area ratio <20%) (group2, n=30), and normal subjects (group3, n=40). The lengths of the anterior (AML) and posterior (PML) mitral leaflets as well as the anterior-posterior mitral annular dimension (MAD) were measured to reflect the degree of ML growth and mitral annular dilation. The ratio of AML and PML to MAD (AML: MAD, PML: MAD) were calculated respectively to assess the adequacy of ML growth in the context of mitral annular dilation. Results: The AML, PML, and the MAD were all increased in patients with LV systolic dysfunction (group1 and group2) compared with normal subjects (group3). In patients with LV systolic dysfunction, both PML and MAD were further increased in group1 compared with group2. However, AML showed no significant difference between the 2 groups. As a result, PML:MAD showed no significant difference between group1 and group2, while AML:MAD was significantly decreased in group1 compared with group2 (Table 1). Conclusion: Mitral leaflet growth occurs in patients with non-ischemic LV systolic dysfunction. Insufficient growth of the anterior mitral leaflet relative to dilated mitral annulus is associated with the development of significant FMR.

Ex Vivo Model of Ischemic Mitral Regurgitation and Analysis of Adjunctive Papillary Muscle Repair

2021 ◽  
Author(s):  
Annabel M. Imbrie-Moore ◽  
Yuanjia Zhu ◽  
Tabitha Bandy-Vizcaino ◽  
Matthew H. Park ◽  
Robert J. Wilkerson ◽  
...  
Keyword(s):  
Mitral Regurgitation ◽  
Papillary Muscle ◽  
Ex Vivo ◽  
Ischemic Mitral Regurgitation ◽  
Muscle Repair ◽  
Ex Vivo Model

Papillary Muscle Sling Placement for Functional Mitral Regurgitation during Minimally Invasive Valve Surgery

2012 ◽  
Vol 7 (6) ◽  
pp. 448-451 ◽  
Author(s):  
Alexandre M. Benjo ◽  
Franscisco Y.B. Macedo ◽  
Orlando Santana ◽  
Joseph Lamelas
Keyword(s):  
New York ◽  
Mitral Regurgitation ◽  
Minimally Invasive ◽  
Papillary Muscle ◽  
Heart Association ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Functional Mitral Regurgitation ◽  
Ventricular Ejection Fraction ◽  
Sling Placement

Herein, we report a case of a 39-year-old woman with an 18-month history of peripartum cardiomyopathy. Transthoracic echocardiography revealed severe functional mitral regurgitation and a left ventricular ejection fraction of 20%. Despite optimal medical therapy, she was in New York Heart Association heart failure class IV, with dyspnea on minimal exertion. The patient underwent minimally invasive mitral valve repair with placement of a papillary muscle sling, which improved her symptoms.

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